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5f7d05ecfd
SynthFS needs a QLIST_INSERT_HEAD_RCU to make sure list instructions are not re-ordered and therefore avoiding a crash. There may be parallel readers which should be allowed for lock-free access and this variant allows us to get rid of rwlocks used by readers. SynthFS is a special case where we dont really need full RCU capabilities as it doesnt allow list entry deletion but concurrent readers/writers and instruction re-ordering should not result in a crash. Also, once the real rcu is available, dummy rcu macro definitions will go away and the code will still work as expected. This patchwork is based on inputs from Paolo Bonzini. Signed-off-by: Harsh Prateek Bora <harsh@linux.vnet.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
463 lines
23 KiB
C
463 lines
23 KiB
C
/* $NetBSD: queue.h,v 1.52 2009/04/20 09:56:08 mschuett Exp $ */
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/*
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* Qemu version: Copy from netbsd, removed debug code, removed some of
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* the implementations. Left in lists, simple queues, tail queues and
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* circular queues.
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*/
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/*
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)queue.h 8.5 (Berkeley) 8/20/94
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*/
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#ifndef QEMU_SYS_QUEUE_H_
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#define QEMU_SYS_QUEUE_H_
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/*
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* This file defines four types of data structures:
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* lists, simple queues, tail queues, and circular queues.
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*
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* A list is headed by a single forward pointer (or an array of forward
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* pointers for a hash table header). The elements are doubly linked
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* so that an arbitrary element can be removed without a need to
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* traverse the list. New elements can be added to the list before
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* or after an existing element or at the head of the list. A list
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* may only be traversed in the forward direction.
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*
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* A simple queue is headed by a pair of pointers, one the head of the
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* list and the other to the tail of the list. The elements are singly
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* linked to save space, so elements can only be removed from the
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* head of the list. New elements can be added to the list after
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* an existing element, at the head of the list, or at the end of the
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* list. A simple queue may only be traversed in the forward direction.
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*
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* A tail queue is headed by a pair of pointers, one to the head of the
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* list and the other to the tail of the list. The elements are doubly
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* linked so that an arbitrary element can be removed without a need to
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* traverse the list. New elements can be added to the list before or
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* after an existing element, at the head of the list, or at the end of
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* the list. A tail queue may be traversed in either direction.
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*
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* A circle queue is headed by a pair of pointers, one to the head of the
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* list and the other to the tail of the list. The elements are doubly
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* linked so that an arbitrary element can be removed without a need to
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* traverse the list. New elements can be added to the list before or after
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* an existing element, at the head of the list, or at the end of the list.
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* A circle queue may be traversed in either direction, but has a more
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* complex end of list detection.
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*
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* For details on the use of these macros, see the queue(3) manual page.
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*/
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#include "qemu-barrier.h" /* for smp_wmb() */
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/*
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* List definitions.
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*/
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#define QLIST_HEAD(name, type) \
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struct name { \
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struct type *lh_first; /* first element */ \
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}
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#define QLIST_HEAD_INITIALIZER(head) \
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{ NULL }
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#define QLIST_ENTRY(type) \
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struct { \
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struct type *le_next; /* next element */ \
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struct type **le_prev; /* address of previous next element */ \
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}
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/*
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* List functions.
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*/
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#define QLIST_INIT(head) do { \
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(head)->lh_first = NULL; \
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} while (/*CONSTCOND*/0)
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#define QLIST_INSERT_AFTER(listelm, elm, field) do { \
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if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
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(listelm)->field.le_next->field.le_prev = \
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&(elm)->field.le_next; \
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(listelm)->field.le_next = (elm); \
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(elm)->field.le_prev = &(listelm)->field.le_next; \
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} while (/*CONSTCOND*/0)
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#define QLIST_INSERT_BEFORE(listelm, elm, field) do { \
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(elm)->field.le_prev = (listelm)->field.le_prev; \
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(elm)->field.le_next = (listelm); \
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*(listelm)->field.le_prev = (elm); \
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(listelm)->field.le_prev = &(elm)->field.le_next; \
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} while (/*CONSTCOND*/0)
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#define QLIST_INSERT_HEAD(head, elm, field) do { \
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if (((elm)->field.le_next = (head)->lh_first) != NULL) \
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(head)->lh_first->field.le_prev = &(elm)->field.le_next;\
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(head)->lh_first = (elm); \
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(elm)->field.le_prev = &(head)->lh_first; \
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} while (/*CONSTCOND*/0)
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#define QLIST_INSERT_HEAD_RCU(head, elm, field) do { \
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(elm)->field.le_prev = &(head)->lh_first; \
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(elm)->field.le_next = (head)->lh_first; \
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smp_wmb(); /* fill elm before linking it */ \
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if ((head)->lh_first != NULL) { \
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(head)->lh_first->field.le_prev = &(elm)->field.le_next; \
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} \
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(head)->lh_first = (elm); \
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smp_wmb(); \
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} while (/* CONSTCOND*/0)
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#define QLIST_REMOVE(elm, field) do { \
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if ((elm)->field.le_next != NULL) \
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(elm)->field.le_next->field.le_prev = \
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(elm)->field.le_prev; \
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*(elm)->field.le_prev = (elm)->field.le_next; \
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} while (/*CONSTCOND*/0)
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#define QLIST_FOREACH(var, head, field) \
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for ((var) = ((head)->lh_first); \
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(var); \
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(var) = ((var)->field.le_next))
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#define QLIST_FOREACH_SAFE(var, head, field, next_var) \
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for ((var) = ((head)->lh_first); \
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(var) && ((next_var) = ((var)->field.le_next), 1); \
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(var) = (next_var))
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/*
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* List access methods.
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*/
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#define QLIST_EMPTY(head) ((head)->lh_first == NULL)
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#define QLIST_FIRST(head) ((head)->lh_first)
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#define QLIST_NEXT(elm, field) ((elm)->field.le_next)
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/*
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* Simple queue definitions.
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*/
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#define QSIMPLEQ_HEAD(name, type) \
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struct name { \
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struct type *sqh_first; /* first element */ \
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struct type **sqh_last; /* addr of last next element */ \
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}
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#define QSIMPLEQ_HEAD_INITIALIZER(head) \
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{ NULL, &(head).sqh_first }
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#define QSIMPLEQ_ENTRY(type) \
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struct { \
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struct type *sqe_next; /* next element */ \
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}
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/*
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* Simple queue functions.
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*/
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#define QSIMPLEQ_INIT(head) do { \
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(head)->sqh_first = NULL; \
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(head)->sqh_last = &(head)->sqh_first; \
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} while (/*CONSTCOND*/0)
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#define QSIMPLEQ_INSERT_HEAD(head, elm, field) do { \
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if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
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(head)->sqh_last = &(elm)->field.sqe_next; \
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(head)->sqh_first = (elm); \
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} while (/*CONSTCOND*/0)
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#define QSIMPLEQ_INSERT_TAIL(head, elm, field) do { \
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(elm)->field.sqe_next = NULL; \
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*(head)->sqh_last = (elm); \
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(head)->sqh_last = &(elm)->field.sqe_next; \
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} while (/*CONSTCOND*/0)
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#define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
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if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL) \
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(head)->sqh_last = &(elm)->field.sqe_next; \
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(listelm)->field.sqe_next = (elm); \
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} while (/*CONSTCOND*/0)
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#define QSIMPLEQ_REMOVE_HEAD(head, field) do { \
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if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\
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(head)->sqh_last = &(head)->sqh_first; \
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} while (/*CONSTCOND*/0)
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#define QSIMPLEQ_REMOVE(head, elm, type, field) do { \
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if ((head)->sqh_first == (elm)) { \
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QSIMPLEQ_REMOVE_HEAD((head), field); \
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} else { \
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struct type *curelm = (head)->sqh_first; \
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while (curelm->field.sqe_next != (elm)) \
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curelm = curelm->field.sqe_next; \
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if ((curelm->field.sqe_next = \
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curelm->field.sqe_next->field.sqe_next) == NULL) \
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(head)->sqh_last = &(curelm)->field.sqe_next; \
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} \
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} while (/*CONSTCOND*/0)
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#define QSIMPLEQ_FOREACH(var, head, field) \
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for ((var) = ((head)->sqh_first); \
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(var); \
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(var) = ((var)->field.sqe_next))
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#define QSIMPLEQ_FOREACH_SAFE(var, head, field, next) \
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for ((var) = ((head)->sqh_first); \
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(var) && ((next = ((var)->field.sqe_next)), 1); \
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(var) = (next))
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#define QSIMPLEQ_CONCAT(head1, head2) do { \
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if (!QSIMPLEQ_EMPTY((head2))) { \
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*(head1)->sqh_last = (head2)->sqh_first; \
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(head1)->sqh_last = (head2)->sqh_last; \
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QSIMPLEQ_INIT((head2)); \
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} \
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} while (/*CONSTCOND*/0)
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#define QSIMPLEQ_LAST(head, type, field) \
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(QSIMPLEQ_EMPTY((head)) ? \
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NULL : \
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((struct type *)(void *) \
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((char *)((head)->sqh_last) - offsetof(struct type, field))))
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/*
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* Simple queue access methods.
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*/
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#define QSIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL)
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#define QSIMPLEQ_FIRST(head) ((head)->sqh_first)
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#define QSIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
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/*
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* Tail queue definitions.
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*/
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#define Q_TAILQ_HEAD(name, type, qual) \
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struct name { \
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qual type *tqh_first; /* first element */ \
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qual type *qual *tqh_last; /* addr of last next element */ \
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}
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#define QTAILQ_HEAD(name, type) Q_TAILQ_HEAD(name, struct type,)
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#define QTAILQ_HEAD_INITIALIZER(head) \
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{ NULL, &(head).tqh_first }
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#define Q_TAILQ_ENTRY(type, qual) \
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struct { \
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qual type *tqe_next; /* next element */ \
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qual type *qual *tqe_prev; /* address of previous next element */\
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}
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#define QTAILQ_ENTRY(type) Q_TAILQ_ENTRY(struct type,)
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/*
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* Tail queue functions.
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*/
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#define QTAILQ_INIT(head) do { \
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(head)->tqh_first = NULL; \
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(head)->tqh_last = &(head)->tqh_first; \
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} while (/*CONSTCOND*/0)
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#define QTAILQ_INSERT_HEAD(head, elm, field) do { \
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if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
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(head)->tqh_first->field.tqe_prev = \
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&(elm)->field.tqe_next; \
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else \
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(head)->tqh_last = &(elm)->field.tqe_next; \
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(head)->tqh_first = (elm); \
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(elm)->field.tqe_prev = &(head)->tqh_first; \
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} while (/*CONSTCOND*/0)
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#define QTAILQ_INSERT_TAIL(head, elm, field) do { \
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(elm)->field.tqe_next = NULL; \
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(elm)->field.tqe_prev = (head)->tqh_last; \
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*(head)->tqh_last = (elm); \
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(head)->tqh_last = &(elm)->field.tqe_next; \
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} while (/*CONSTCOND*/0)
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#define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
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if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
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(elm)->field.tqe_next->field.tqe_prev = \
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&(elm)->field.tqe_next; \
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else \
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(head)->tqh_last = &(elm)->field.tqe_next; \
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(listelm)->field.tqe_next = (elm); \
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(elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
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} while (/*CONSTCOND*/0)
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#define QTAILQ_INSERT_BEFORE(listelm, elm, field) do { \
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(elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
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(elm)->field.tqe_next = (listelm); \
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*(listelm)->field.tqe_prev = (elm); \
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(listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
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} while (/*CONSTCOND*/0)
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#define QTAILQ_REMOVE(head, elm, field) do { \
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if (((elm)->field.tqe_next) != NULL) \
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(elm)->field.tqe_next->field.tqe_prev = \
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(elm)->field.tqe_prev; \
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else \
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(head)->tqh_last = (elm)->field.tqe_prev; \
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*(elm)->field.tqe_prev = (elm)->field.tqe_next; \
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} while (/*CONSTCOND*/0)
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#define QTAILQ_FOREACH(var, head, field) \
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for ((var) = ((head)->tqh_first); \
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(var); \
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(var) = ((var)->field.tqe_next))
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#define QTAILQ_FOREACH_SAFE(var, head, field, next_var) \
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for ((var) = ((head)->tqh_first); \
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(var) && ((next_var) = ((var)->field.tqe_next), 1); \
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(var) = (next_var))
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#define QTAILQ_FOREACH_REVERSE(var, head, headname, field) \
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for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last)); \
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(var); \
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(var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)))
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/*
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* Tail queue access methods.
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*/
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#define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL)
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#define QTAILQ_FIRST(head) ((head)->tqh_first)
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#define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
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#define QTAILQ_LAST(head, headname) \
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(*(((struct headname *)((head)->tqh_last))->tqh_last))
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#define QTAILQ_PREV(elm, headname, field) \
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(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
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/*
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* Circular queue definitions.
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*/
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#define QCIRCLEQ_HEAD(name, type) \
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struct name { \
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struct type *cqh_first; /* first element */ \
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struct type *cqh_last; /* last element */ \
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}
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#define QCIRCLEQ_HEAD_INITIALIZER(head) \
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{ (void *)&head, (void *)&head }
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#define QCIRCLEQ_ENTRY(type) \
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struct { \
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struct type *cqe_next; /* next element */ \
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struct type *cqe_prev; /* previous element */ \
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}
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/*
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* Circular queue functions.
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*/
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#define QCIRCLEQ_INIT(head) do { \
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(head)->cqh_first = (void *)(head); \
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(head)->cqh_last = (void *)(head); \
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} while (/*CONSTCOND*/0)
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#define QCIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
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(elm)->field.cqe_next = (listelm)->field.cqe_next; \
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(elm)->field.cqe_prev = (listelm); \
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if ((listelm)->field.cqe_next == (void *)(head)) \
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(head)->cqh_last = (elm); \
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else \
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(listelm)->field.cqe_next->field.cqe_prev = (elm); \
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(listelm)->field.cqe_next = (elm); \
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} while (/*CONSTCOND*/0)
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#define QCIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
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(elm)->field.cqe_next = (listelm); \
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(elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
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if ((listelm)->field.cqe_prev == (void *)(head)) \
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(head)->cqh_first = (elm); \
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else \
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(listelm)->field.cqe_prev->field.cqe_next = (elm); \
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(listelm)->field.cqe_prev = (elm); \
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} while (/*CONSTCOND*/0)
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#define QCIRCLEQ_INSERT_HEAD(head, elm, field) do { \
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(elm)->field.cqe_next = (head)->cqh_first; \
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(elm)->field.cqe_prev = (void *)(head); \
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if ((head)->cqh_last == (void *)(head)) \
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(head)->cqh_last = (elm); \
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else \
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(head)->cqh_first->field.cqe_prev = (elm); \
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(head)->cqh_first = (elm); \
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} while (/*CONSTCOND*/0)
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#define QCIRCLEQ_INSERT_TAIL(head, elm, field) do { \
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(elm)->field.cqe_next = (void *)(head); \
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(elm)->field.cqe_prev = (head)->cqh_last; \
|
|
if ((head)->cqh_first == (void *)(head)) \
|
|
(head)->cqh_first = (elm); \
|
|
else \
|
|
(head)->cqh_last->field.cqe_next = (elm); \
|
|
(head)->cqh_last = (elm); \
|
|
} while (/*CONSTCOND*/0)
|
|
|
|
#define QCIRCLEQ_REMOVE(head, elm, field) do { \
|
|
if ((elm)->field.cqe_next == (void *)(head)) \
|
|
(head)->cqh_last = (elm)->field.cqe_prev; \
|
|
else \
|
|
(elm)->field.cqe_next->field.cqe_prev = \
|
|
(elm)->field.cqe_prev; \
|
|
if ((elm)->field.cqe_prev == (void *)(head)) \
|
|
(head)->cqh_first = (elm)->field.cqe_next; \
|
|
else \
|
|
(elm)->field.cqe_prev->field.cqe_next = \
|
|
(elm)->field.cqe_next; \
|
|
} while (/*CONSTCOND*/0)
|
|
|
|
#define QCIRCLEQ_FOREACH(var, head, field) \
|
|
for ((var) = ((head)->cqh_first); \
|
|
(var) != (const void *)(head); \
|
|
(var) = ((var)->field.cqe_next))
|
|
|
|
#define QCIRCLEQ_FOREACH_REVERSE(var, head, field) \
|
|
for ((var) = ((head)->cqh_last); \
|
|
(var) != (const void *)(head); \
|
|
(var) = ((var)->field.cqe_prev))
|
|
|
|
/*
|
|
* Circular queue access methods.
|
|
*/
|
|
#define QCIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
|
|
#define QCIRCLEQ_FIRST(head) ((head)->cqh_first)
|
|
#define QCIRCLEQ_LAST(head) ((head)->cqh_last)
|
|
#define QCIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
|
|
#define QCIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
|
|
|
|
#define QCIRCLEQ_LOOP_NEXT(head, elm, field) \
|
|
(((elm)->field.cqe_next == (void *)(head)) \
|
|
? ((head)->cqh_first) \
|
|
: (elm->field.cqe_next))
|
|
#define QCIRCLEQ_LOOP_PREV(head, elm, field) \
|
|
(((elm)->field.cqe_prev == (void *)(head)) \
|
|
? ((head)->cqh_last) \
|
|
: (elm->field.cqe_prev))
|
|
|
|
#endif /* !QEMU_SYS_QUEUE_H_ */
|